Radio communication node

ABSTRACT

When a transmission timing of a downlink and a reception timing of an uplink at a radio communication node  100 B are aligned, a radio communication node  100 A determines an alignment value of the reception timing based on timing information used to determine transmission timing of the uplink, or an offset value from the timing information. The radio communication node  100 A transmits the determined alignment value or offset value to the radio communication node  100 B.

TECHNICAL FIELD

The present invention relates to a radio communication node thatconfigures radio access and radio backhaul.

BACKGROUND ART

The 3rd Generation Partnership Project (3GPP) specifies Long TermEvolution (LTE) and specifies LTE-Advanced (hereinafter referred to asLTE including LTE-Advanced) and post-LTE systems called 5G New Radio(NR) or Next Generation (NG) for the purpose of further increasing thespeed of LTE.

For example, in a radio access network (RAN) of NR, integrated accessand backhaul (IAB) in which radio access to a terminal (User Equipment,UE) and radio backhaul between radio communication nodes such as radiobase stations (gNB) are integrated is being discussed (see Non PatentLiterature 1).

In the IAB, an IAB node has a Mobile Termination (MT) that is a functionfor connecting to a parent node (which may also be called an IAB donor)and a Distributed Unit (DU) that is a function for connecting to a childnode or a UE.

In 3GPP Release 16, radio access and radio backhaul are based onhalf-duplex and time division multiplexing (TDM). Also, in Release 17and later, application of space division multiplexing (SDM) andfrequency division multiplexing (FDM) is being discussed.

In Non Patent Literature 1, seven cases are specified regarding thealignment of transmission timing between a parent node and an IAB node.For example, as a premise, alignment of downlink (DL) transmissiontiming between an IAB node and an IAB donor (Case #1), alignment of DLand uplink (UL) reception timings at an IAB node (Case #3), andcombination of alignment of DL transmission timing of Case #1 and ULreception timing of Case #3 (Case #7) are specified.

In Case #1, in order to match the DL transmission timing at the DU ofeach node, it is agreed that the IAB node uses a calculating formula(TA/2+T_delta) to calculate propagation delay (T_(propagation_0)) ofpath (0) with the parent node and transmit the transmission timing asoffset.

Here, TA is a value of Timing Advance for determining the transmissiontiming of the UE specified in 3GPP Release 15, and T_delta is determinedconsidering the switching time from reception to transmission of theparent node.

CITATION LIST Non Patent Literature

Non Patent Literature 1: 3GPP TR 38.874 V16.0.0, 3rd GenerationPartnership Project; Technical Specification Group Radio Access Network;NR; Study on Integrated Access and Backhaul; (Release 16), 3GPP,December 2018

SUMMARY OF INVENTION

As described above, in Case #7, it is necessary to realize not onlyalignment of DL transmission timing of Case #1, specifically, an IABnode and an IAB donor DU, but also alignment of Case #3, specifically,DL and UL reception timings at an IAB node.

That is, in the case of supporting Case #7, it is necessary to match theDL and UL reception timings of an IAB node in addition to the DLtransmission timing between a gNB and an IAB node.

Therefore, the present invention has been made in view of suchcircumstances, and an object of the present invention is to provide aradio communication node capable of reliably matching transmissiontiming and reception timing of a Distributed Unit (DU) and a MobileTermination (MT) in an Integrated Access and Backhaul (IAB).

According to one aspect of the present disclosure, a radio communicationnode (for example, a radio communication node 100A) includes: a controlunit (control unit 140) configured to, when a transmission timing of adownlink and a reception timing of an uplink at a lower node (forexample, a radio communication node 100B) are aligned, determine analignment value of the reception timing based on timing information (TA)used to determine transmission timing of the uplink, or an offset valuefrom the timing information; and a transmitting unit (for example, atiming related information transmitting unit 150) configured to transmitthe alignment value or the offset value to the lower node.

According to one aspect of the present disclosure, a radio communicationnode (for example, a radio communication node 100B) includes: a controlunit (control unit 170) configured to, when a transmission timing of adownlink and a reception timing of an uplink at the radio communicationnode are aligned, determine an aligning method of the transmissiontiming of the downlink and the reception timing of the uplink, based ondownlink control information from an upper node, or the transmissiontiming of the downlink and the reception timing of the uplink; and atransceiving unit (for example, a radio transmitting unit 161 and aradio receiving unit 162) configured to receive the uplink from a lowernode and transmit the downlink to the lower node, based on thedetermined aligning method.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall schematic configuration diagram of a radiocommunication system 10.

FIG. 2 is a diagram illustrating a basic configuration example of anIAB.

FIG. 3 is a functional block configuration diagram of a radiocommunication node 100A.

FIG. 4 is a functional block configuration diagram of a radiocommunication node 100B.

FIG. 5 is a diagram illustrating an example of a relationship ofT_(propagation_0), TA, and T_delta.

FIG. 6 is a diagram illustrating an example of symbol-level timingalignment at a parent node and an IAB node in Case #7.

FIG. 7 is a diagram illustrating an example of slot-level timingalignment at a parent node and an IAB node in Case #7.

FIG. 8 is a diagram illustrating an example of slot-level timingalignment (including Tp and T1) at a parent node in Case #7.

FIG. 9 is a diagram illustrating a configuration example of RandomAccess Response (PAR) and MAC-CE.

FIG. 10 is a diagram illustrating an example of timing alignment at aparent node and an IAB node according to 3GPP Release-15 (Legacy), Case#6, and Case #7.

FIG. 11 is a diagram illustrating an example of a hardware configurationof a CU 50 and radio communication nodes 100A to 100C.

DESCRIPTION OF EMBODIMENTS

Hereinafter, embodiments will be described with reference to thedrawings. It should be noted that the same functions or configurationsare denoted by the same or similar reference numerals, and a descriptionthereof will be omitted as appropriate.

(1) Overall Schematic Configuration of Radio Communication System

FIG. 1 is an overall schematic configuration diagram of a radiocommunication system 10 according to the present embodiment. The radiocommunication system 10 is a radio communication system in accordancewith 5G New Radio (NR) and includes a plurality of radio communicationnodes and a terminal.

Specifically, the radio communication system 10 includes radiocommunication nodes 100A, 100B, and 100C and a terminal 200 (hereinafterUE 200, User Equipment).

The radio communication nodes 100A, 100B, and 100C can configure radioaccess with the UE 200 and radio backhaul (BH) between the radiocommunication nodes. Specifically, a backhaul (transmission path) isconfigured by a radio link between the radio communication node 100A andthe radio communication node 100B and between the radio communicationnode 100A and the radio communication node 100C.

As such, the configuration in which the radio access with the UE 200 andthe radio backhaul between the radio communication nodes are integratedis referred to as Integrated Access and Backhaul (LAB).

The IAB reuses existing functions and interfaces defined for radioaccess. In particular, Mobile-Termination (MT), gNB-DU (DistributedUnit), gNB-CU (Central Unit), User Plane Function (UPF), Access andMobility Management Function (AMF) and Session Management Function(SMF), and corresponding interfaces, for example, NR Uu (between MT andgNB/DU), F1, NG, X2 and N4, are used as base line.

The radio communication node 100A is connected with an NR radio accessnetwork (NG-RAN) and a core network (Next Generation Core (NGC) or 5GC)via a wired transmission path such as a fiber transport. The NG-RAN/NGCincludes a Central Unit 50 (hereinafter CU 50) that is a communicationnode. It should be noted that the NG-RAN and the NGC may be simplyreferred to as “network”.

It should be noted that the CU 50 may be constituted by any one of UPF,AMF, and SMF described above, or a combination thereof. Alternatively,the CU 50 may be a gNB-CU as described above.

FIG. 2 is a diagram illustrating a basic configuration example of anIAB. As illustrated in FIG. 2 , in the present embodiment, the radiocommunication node 100A constitutes a parent node in the IAB, and theradio communication node 100B (and the radio communication node 100C)constitutes an IAB node in the IAB. It should be noted that the parentnode may be called an IAB donor.

A child node in the IAB is constituted by another radio communicationnode not illustrated in FIG. 1 .

Alternatively, the UE 200 may constitute the child node.

The radio link is configured between the parent node and the IAB node.Specifically, the radio link called Link_parent is configured.

The radio link is configured between the IAB node and the child node.Specifically, the radio link called Link_child is configured.

The radio link configured between such radio communication nodes iscalled a radio backhaul link. Link_parent is constituted by a DL ParentBH in the downlink (DL) direction and a UL Parent BH in the uplink (UL)direction. Link_child is constituted by a DL Child BH in the DLdirection and a UL Child BH in the UL direction.

That is, in the IAB, the direction from the parent node to the childnode (including the UE 200) is the DL direction, and the direction fromthe child node to the parent node is the UL direction.

It should be noted that the radio link configured between the UE 200 andthe IAB node or the parent node is called a radio access link.Specifically, the radio link is constituted by DL Access in the DLdirection and UL Access in the UL direction.

The IAB node has a Mobile Termination (MT) that is the function forconnecting to the parent node and a Distributed Unit (DU) that is thefunction for connecting to the child node (or the UE 200). It should benoted that the child node may be called a lower node.

Similarly, the parent node has an MT for connecting to an upper node anda DU for connecting to a lower node such as an IAB node. It should benoted that the parent node may have a CU (Central Unit) instead of theMT.

Also, similarly to the IAB node and the parent node, the child node alsohas an MT for connecting to the upper node such as the IAB node and a DUfor connecting to the lower node such as the UE 200.

In the radio resources used by the DU, from the viewpoint of the DU, DL,UL and flexible time-resources (D/U/F) are classified into any type ofhard, soft, or not available (H/S/NA). Also, even in the soft (S),available or not available is specified.

It should be noted that the configuration example of the IAB illustratedin FIG. 2 uses CU/DU division, but the configuration of the IAB is notnecessarily limited thereto. For example, in the radio backhaul, the IABis constituted by tunneling using GPRS Tunneling Protocol (GTP)-U/UserDatagram Protocol (UDP)/Internet Protocol (IP).

The main advantage of such an IAB is that NR cells can be flexibly anddensely arranged without densifying a transport network. The IAB can beapplied to various scenarios such as outdoor small cell arrangement,indoors, and support of even mobile relay (for example, buses andtrains).

Also, as illustrated in FIGS. 1 and 2 , the IAB may also support NR-onlystandalone (SA) deployment, or non-standalone (NSA) deployment thatinclude other RATs (such as LTE).

In the present embodiment, the radio access and the radio backhauloperate based on half-duplex. However, the radio access and the radiobackhaul are not necessarily limited to half-duplex, and full-duplex mayalso be used as long as the requirements are satisfied.

Also, as the multiplexing scheme, time division multiplexing (TDM),space division multiplexing (SDM), and frequency division multiplexing(FDM) can be used.

When the IAB node operates in half-duplex, the DL Parent BH is thereceiving (RX) side, the UL Parent BH is the transmitting (TX) side, theDL Child BH is the transmitting (TX) side, and the UL Child BH is thereceiving (RX) side. Also, in the case of Time Division Duplex (TDD),the DL/UL configuration pattern at the IAB node is not limited toDL-F-UL, and the configuration pattern such as UL-F-DL is applied onlyto the radio backhaul (BH).

Also, in the present embodiment, the simultaneous operation of the DUand MT of the IAB node is realized by using SDM/FDM.

(2) Functional Block Configuration of Radio Communication System

Next, the functional block configurations of the radio communicationnode 100A and the radio communication node 100B that constitute theradio communication system 10 will be described.

(2.1) Radio Communication Node 100A

FIG. 3 is a functional block configuration diagram of the radiocommunication node 100A that constitutes the parent node. As illustratedin FIG. 3 , the radio communication node 100A includes a radiotransmitting unit 110, a radio receiving unit 120, an NW IF unit 130, acontrol unit 140, and a timing related information transmitting unit150.

The radio transmitting unit 110 transmits a radio signal in accordancewith the 5G specifications. Also, the radio receiving unit 120 transmitsa radio signal in accordance with the 5G specifications. In the presentembodiment, the radio transmitting unit 110 and the radio receiving unit120 perform radio communication with the radio communication node 100Bthat constitutes the IAB node.

In the present embodiment, the radio communication node 100A has thefunctions of the MT and the DU, and the radio transmitting unit 110 andthe radio receiving unit 120 also transmit and receive radio signalscorresponding to the MT/DU.

The NW IF unit 130 provides a communication interface that realizes aconnection with the NGC side or the like. For example, the NW IF unit130 may include interfaces such as X2, Xn, N2, and N3.

The control unit 140 performs control of each functional block thatconstitutes the radio communication node 100A. In particular, in thepresent embodiment, the control unit 140 controls the DL and ULtransmission timings and the UL reception timing. Specifically, thecontrol unit 140 can align the DL transmission timing and the ULtransmission timing at the lower node, for example, the radiocommunication node 100B (LAB node). Also, the control unit 140 can alignthe UL reception timing at the radio communication node 100B (LAB node).

That the control unit 140 aligns the DL transmission timing of eachradio communication node including the radio communication node 100A maycorrespond to Case #1 specified in 3GPP TR 38.874, as described below.

Also, the alignment of the DL and UL transmission timings at the IABnode may correspond to Case #2. Furthermore, the alignment of the DL andUL reception timings at the IAB node may correspond to Case #3.

It should be noted that the alignment at the IAB node may include thealignment of the DL transmission timing at the IAB node, and the DL andUL transmission timings may be aligned at the IAB node.

That is, the control unit 140 can support Case #6 that is a combinationof alignments of the DL transmission timing of Case #1 and the ULtransmission timing of Case #2.

Furthermore, the alignment at the IAB node may include the alignment ofthe DL transmission timing at the IAB node, and the DL and UL receptiontimings may be aligned at the IAB node.

That is, the control unit 140 can support Case #7 that is a combinationof alignments of the DL transmission timing of Case #1 and the ULreception timing of Case #3.

The control unit 140 can obtain a propagation delay between the radiocommunication node 100A (parent node) and the radio communication node100B (lower node).

Specifically, the control unit 140 calculates the propagation delay ofthe path (0) between the parent node and the lower node based on(Equation 1).

T _(propagation_0)=(TA/2+T_delta)  (Equation 1)

TA is a value of Timing Advance (TA) for determining the transmissiontiming of the UE specified in 3GPP Release 15. Here, TA may be calledtiming information.

Also, T_delta is determined considering the switching time fromreception to transmission of the parent node. The method of calculatingT_(propagation_0) will be described below in more detail.

As described above, when the control unit 140 aligns the DL transmissiontiming and the UL transmission timing at the IAB node (which may be readas the case corresponding to Case #6), the control unit 140 may obtainthe propagation delay between the radio communication node 100A (parentnode) and the radio communication node 100B (lower node) used fordetermining the DL transmission timing, and the propagation delaybetween the radio communication node 100A and the radio communicationnode 100B used for determining the UL transmission timing at the radiocommunication node 100B.

It should be noted that the propagation delay may mean T_(propagation_0)or may mean TA/2 or TA. Also, the propagation delay may be called thetransmission time, delay time, or simply delay, and may be called byother names as long as they indicate the time required for DL or ULtransmission between the radio communication nodes constituting the IAB.

Also, when the control unit 140 aligns the DL transmission timing andthe UL reception timing at the lower node (which may be read as the casecorresponding to Case #7), the control unit 140 may determine the timinginformation used for determining the UL transmission timing,specifically, the alignment value of the reception timing based on theTA or the offset value from the timing information (TA).

Here, the alignment value of the reception timing based on the TA may bea value in which information (for example, 1 bit) indicating positive(+) or negative (−) is added to a TA value by a TA command in a RandomAccess Response (RAR). Also, the alignment value may be only informationindicating negative or may be another value associated with beingnegative.

Alternatively, the TA value (NTA) may be an expanded value.Specifically, in 3GPP Release-15, NTA can take a value of 0, 1, 2, . . ., 3846, but the alignment value of the reception timing based on the TAmay be a negative value obtained by subtraction from 3846 using thevalue of 3847 to 4095. It should be noted that, in the case of 3847 orlater, it may be treated as an implicitly applied negative value withoutnecessarily subtracting.

Also, the offset value from the timing information (TA) may indicate anoffset (time) from the TA value specified in 3GPP Release 15 or the TAvalue in the case corresponding to Case #6 described above. It should benoted that the offset value may be a value based on the TA or may not bea value based on the TA as long as the offset time can be determined.

The timing related information transmitting unit 150 transmits, to thelower node, information about the DL or UL transmission timing orreception timing (which may also be called timing related information).Specifically, the timing related information transmitting unit 150 cantransmit information about the DL or UL transmission timing or receptiontiming to the IAB node and/or the child node.

Also, the timing related information transmitting unit 150 can transmit,to the lower node, the alignment value of the reception timing based onthe TA described above or the offset value from the TA.

The timing information (TA) can be transmitted by using a TA command ina Random Access Response (RAR) or a Medium Access Control-ControlElement (MAC-CE). Similarly, the information indicating that the DLtransmission timing and the UL transmission timing or reception timingat the IAB node are aligned and the timing related informationindicating the alignment value and the offset value described above mayalso be transmitted by using the MAC-CE, but may be transmitted by usingsignaling of an appropriate channel or an upper layer (such as radioresource control layer (RRC)).

Also, the timing information and the timing related information may alsobe transmitted by using signaling of an appropriate channel or an upperlayer.

The channel includes a control channel and a data channel. The controlchannel includes a Physical Downlink Control Channel (PDCCH), a PhysicalUplink Control Channel (PUCCH), a Physical Random Access Channel(PRACH), and a Physical Broadcast Channel (PBCH).

Also, the data channel includes a Physical Downlink Shared Channel(PDSCH) and a Physical Uplink Shared Channel (PUSCH).

It should be noted that a reference signal includes a DemodulationReference Signal (DMRS), a Sounding Reference Signal (SRS), a PhaseTracking Reference Signal (PTRS), and a Channel StateInformation-Reference Signal (CSI-RS), and the signal includes thechannel and the reference signal. Also, the data may mean datatransmitted via the data channel.

UCI is control information that is symmetrical with Downlink ControlInformation (DCI), and is transmitted via a PUCCH or a PUSCH. UCI mayinclude a Scheduling Request (SR), a Hybrid Automatic Repeat Request(HARQ) ACK/NACK, and a Channel Quality Indicator (CQI).

(2.1) Radio Communication Node 100B

FIG. 4 is a functional block configuration diagram of the radiocommunication node 100B that constitutes the IAB node. As illustrated inFIG. 4 , the radio communication node 100B includes a radio transmittingunit 161, a radio receiving unit 162, a downlink control informationreceiving unit 165, and a control unit 170.

The radio transmitting unit 161 transmits a radio signal in accordancewith the 5G specifications. Also, the radio receiving unit 162 transmitsa radio signal in accordance with the 5G specifications. In the presentembodiment, the radio transmitting unit 161 and the radio receiving unit162 perform radio communication with the radio communication node 100Aconstituting the parent node and radio communication with the child node(including the case of the UE 200).

Also, the radio transmitting unit 161 and the radio receiving unit 162receive UL from the lower node and transmit DL to the lower node, basedon the aligning method of the DL transmission timing and the ULreception timing determined by the control unit 170. In the presentembodiment, the radio transmitting unit 161 and the radio receiving unit162 constitute a transceiving unit.

The downlink control information receiving unit 165 receives downlinkcontrol information (DCI) from the upper node. Specifically, thedownlink control information receiving unit 165 can receive DCIincluding information indicating the aligning method of the DLtransmission timing and the UL reception timing.

More specifically, the downlink control information receiving unit 165can receive DCI indicating which of Case #1, Case #6, and Case #7 isapplied. That is, Case #1, Case #6, and Case #7 may be dynamicallychanged (switched) in the network.

The control unit 170 performs control of each functional block thatconstitutes the radio communication node 100B. In particular, in thepresent embodiment, the control unit 170 can align the DL transmissiontiming and the UL transmission timing and reception timing at the radiocommunication node 100B (lower node).

Specifically, when the control unit 170 aligns the DL transmissiontiming and the UL transmission timing at the radio communication node100B (lower node), the control unit 170 matches the UL transmissiontiming with the DL transmission timing. That is, the control unit 170uses the DL transmission timing as a reference to match the ULtransmission timing with the DL transmission timing.

Also, when the control unit 170 aligns the DL transmission timing andthe UL reception timing at the radio communication node 100B (which maybe read as the case corresponding to Case #7), the control unit 170 maydetermine the aligning method of the DL transmission timing and the ULreception timing based on the downlink control information (DCI) fromthe upper node or the DL transmission timing and the UL receptiontiming.

Specifically, the control unit 170 may determine which of the aligningmethods of Case #1, Case #6, and Case #7 is applied, based on theinformation included in the received DCI. Alternatively, the controlunit 170 may implicitly determine which of the aligning methods of Case#1, Case #6, and Case #7 is applied, based on the DL transmission timingand the UL reception timing transmitted and received by the radiocommunication node 100B. It should be noted that the operation in whichthe radio communication node 100B (IAB node) implicitly determines whichof the aligning methods of Case #1, Case #6, and Case #7 is applied willbe described below.

Also, the control unit 170 may align the DL transmission timing at theupper node (for example, the radio communication node 100A) and the DLtransmission timing at the radio communication node 100B, based on thetime associated with the switching from UL reception to DL transmission,specifically, T_delta. It should be noted that, in this case, T_deltamay be a value that is half the switching time from reception totransmission in the upper node (parent node). That is, the control unit170 may align the DL transmission timing in consideration of theswitching time from reception to transmission at the parent node.

Also, the alignment of the DL transmission timing may be performed bythe radio communication node 100A.

(3) Operation of Radio Communication System

Next, the operation of the radio communication system 10 will bedescribed. Specifically, the operations associated with the alignmentsof the DL and UL transmission timings and reception timings in the radiocommunication system 10 will be described.

More specifically, the operation of aligning the DL and UL transmissiontimings in the IAB, which is used in the SDM and/or the FDM as themultiplexing scheme, especially the operation of aligning the DL and ULtransmission timings when Case #6 specified in 3GPP TR 38.874 is appliedwill be described.

(3.1) Specified Contents of 3GPP

First, the specified contents of the 3GPP will be briefly described. In3GPP TR 38.874 (for example, V16.0.0), the following seven cases arespecified in order to match the DL or UL transmission timing between theradio communication nodes constituting the IAB.

(Case #1): Alignment of DL transmission timing between IAB node and IABdonor

(Case #2): Alignment of DL and UL transmission timings at IAB node

(Case #3): Alignment of DL and UL reception timings at IAB node

(Case #4): Transmission by Case #2 and reception by Case #3 at IAB node

(Case #5): Application of Case #1 to access link timing and applicationof Case #4 to backhaul link timing at IAB node in different time slots

(Case #6): Alignment of DL transmission timing for Case #1+alignment ofUL transmission timing for Case #2

(Case #7): Alignment of DL transmission timing for Case #1+alignment ofUL reception timing for Case #3

In 3GPP Release 16, as described above, in order to match the DLtransmission timing of the DU between the radio communication nodesconstituting the IAB, it is agreed that the IAB node uses thecalculating formula (TA/2+T_delta) to calculate the propagation delay(T_(propagation_0)) of the path (0) with the parent node and transmitsthe transmission timing as offset.

Here, TA is a value of Timing Advance for determining the transmissiontiming of the UE specified in 3GPP Release 15, and T_delta is determinedconsidering the switching time from reception to transmission of theparent node.

FIG. 5 : is a diagram illustrating an example of a relationship ofT_(propagation_0), TA, and T_delta. As illustrated in FIG. 5 ,T_(propagation_0) is a value obtained by adding T_delta to a valueobtained by halving TAO between the parent node and the IAB node.T_delta may correspond to a value obtained by having a gap (Tg)accompanying the switching time from UL reception to DL transmission atthe parent node.

In the following, the operation associated with the DL and ULtransmission timings when the radio communication node constituting theIAB supports Case #6 in addition to Case #1 will be described. In thecase of supporting Case #6, in addition to Case #1, the UL transmissiontiming of the MT is also matched with the DL transmission timing of theIAB node and the child node DU.

The following contents may be assumed as a premise of an operationexample described below.

-   -   Due to the limitation of half-duplex, one of TDM/SDM/FDM is        applied to the backhaul link and the access link of the IAB        node. In the case of the SDM or the FDM, the DU and the MT can        be transmitted or received at the same time.    -   In the case of supporting SDM/FDM using a single panel, it is        necessary to support Case #6 for simultaneous transmission at        the IAB node, or it is necessary to support Case #7 for        simultaneous reception at the IAB node.    -   Case #1 is supported in both transmission timings of the        backhaul link and the access link.    -   Case #7 is supported only when compatible with the UE of Release        15.    -   The IAB node has to configure the DL transmission timing earlier        than the DL reception timing by TA/2+T_delta.    -   T_delta is notified from the parent node. The value of T_delta        takes into account factors such as the switching time from        transmission to reception (or vice versa) and the offset between        DL transmission and UL reception of the parent node due to        factors such as hardware failure.    -   TA is derived based on the regulations of Release 15. TA is        interpreted as a timing gap between the UL transmission timing        and the DL reception timing.    -   In order to align the DL transmission timing of the IAB node by        configuring the DL transmission timing (TA/2+T_delta) of the IAB        node before the DL reception timing, T_delta needs to be        configured to (−½) of the time interval between the start of the        UL reception frame i of the IAB node and the start of the DL        transmission frame i at the parent node.

Also, the following contents may be assumed regarding the timingalignment of Case #7.

-   -   An effective negative TA and TDM is introduced between the IAB        node/UE that supports the new TA value and the child IAB node/UE        that does not support the new TA value.    -   In order to enable the timing alignment of DL reception and UL        reception at the IAB node, the following operations may be        performed.    -   (Alt. 1): The negative time alignment (TA) of the IAB node that        is applied to the child node of the IAB node is introduced.    -   (Alt. 2): The alignment of symbols (OFDM symbols) is enabled        between DL reception and UL reception at the IAB node, but a        positive TA that does not enable slot alignment is applied.    -   (Alt. 3): Relative offset signaling for the latest negative TA        value applied to the child node of the IAB node is performed.

In the following, the operation example of timing alignment of Case #7assuming (Alt. 1) or (Alt. 3) will be described.

(3.2) Operation Example

In the operation example described below, Over-the-Air (OTA)synchronization of Case #7 (combination of Case #1 and Case #3)described above is realized between the radio communication nodesconstituting the IAB.

(3.2.1) Operation Overview

The following operations may be performed regarding notification oftiming information and timing related information based on Case #3(matching timings of DL reception of parent node MT and UL reception ofDU).

-   -   (Operation Example 1): Negative value is introduced into TA of        MAC RAR.    -   (Operation Example 1-1): Information (which may be 1 bit)        indicating positive (+) or negative (−) is added to TA in MAC        RAR.    -   (Operation Example 1-2): NTA value of MAC RAR is extended.

In 3GPP Release-15 (hereinafter Release-15), 0, 1, 2, . . . , 3846 areused (only positive values), but 3847 to 4095 are added by using emptybits. A negative value is configured by subtracting the value from 3846.

-   -   (Operation Example 2): Offset value from TA value applied to        Release-15 or Case #6 is introduced.

In this case, the TA value notified from the parent node to the IAB nodemay be any of the following values.

-   -   (Alt. 1): TA value of Release-15    -   (Alt. 2): TA value applied to Case #6    -   (Alt. 3): Both of TA values applied to Release-15 and Case #6        may be configurable.

It should be noted that the TA value applied to Case #6 may meanT_(progagation_0), or may mean TA/2 or TA, as described above.

Also, in the case of the operation example 2, the notification of theoffset value from the TA value may be any of the following values.

-   -   (Alt. 1): Following the Release-15 mechanism, an integer value        is notified, and the offset value is calculated by using Tc or        granularity.

It should be noted that Tc is a basic time unit for NR specified in 3GPPTS38.211.

-   -   (Alt. 2): Offset value is notified to IAB node (lower node).    -   (Operation Example 3): Regarding Case #1 (matching transmission        timing of DU of parent node and DU of IAB node), the following        operation may be performed.    -   (Operation Example 3-1): T_delta specified in 3GPP Release-16        (hereinafter Release-16) is used.

In this case, the code of T_delta may be different from the code ofT_delta of Release-16 (T_delta may be half the switching intervalbetween reception and transmission at the parent node).

-   -   (Operation Example 3-2): Timing matching mechanism specified in        3GPP Release-16 is used.    -   (Operation Example 4): When Case #1/Case #6/Case #7 are        dynamically switched, which Case is applied is indicated.

Also, regarding the reception timing alignment in Case #7, the alignmentat the symbol level or slot level is possible.

FIG. 6 illustrates an example of the symbol-level timing alignment atthe parent node and the IAB node in Case #7. Also, FIG. 7 illustrates anexample of the slot-level timing alignment at the parent node and theIAB node in Case #7. It should be noted that the symbol level may meanthat an OFDM symbol transmitted and received between the radiocommunication nodes is used as a reference. Also, the slot level maymean that a slot configured by a predetermined number (for example, 14)of OFDM symbols and constituting part of a radio frame (or subframe) isused as a reference.

As illustrated in FIGS. 6 and 7 , the slot-level reception timingalignment may achieve high resource utilization as compared to thesymbol-level reception timing alignment, but It may cause a situation inwhich the negative TA is required in the IAB node.

Therefore, in the above-described operation example, when the slot-leveltiming alignment of Case #7 is supported by the parent node, theoperations associated with signaling related to the alignment of the ULtransmission timing of the MT at the IAB node and the alignment of theDL transmission timing of the DU at the IAB node is the main operation.

In order to support the slot-level timing alignment of Case #7 at theparent node, the IAB node needs to configure the UL transmission timing(TA=2Tp−T1) of the MT before the DL reception timing of the MT.

FIG. 8 illustrates an example of the slot-level timing alignment(including Tp and T1) at the parent node in Case #7.

Here, Tp may mean the propagation delay between the parent node and theIAB node, and T1 may mean the gap between the DL transmission timing ofthe DU and the DL reception timing of the MT at the parent node.

In this case, TA can be negative. As described above, the negative valuecan be introduced into the TA of the MAC RAR, or can be addressed bysignaling the relative offset with respect to the negative TA value. Inthe following, the signaling operation for alignment of the ULtransmission timing of the MT and the DL transmission timing of the DUat the IAB node will be described in more detail.

(3.2.2) Operation Example 1

In this operation example, a negative initial TA is introduced into theMAC RAR in the alignment of the UL transmission timing of the MT at theIAB node. From the viewpoint of detailed signaling design of MAC RAR,specifically, the following operations may be performed.

-   -   (Operation Example 1-1): One bit is added to indicate negative        or positive TA of MAC RAR.

For example, reserved bits of MAC RAR specified in Release-15 can beused. FIG. 9 illustrates a configuration example of Random AccessResponse (RAR) and MAC-CE. As illustrated in FIG. 9 , in Release 15, theUL frame number for transmission from the UE starts before the start ofthe corresponding DL frame in the UE.

A value (N_TA, offset) may be provided to the UE by RRC signaling, orthe UE may determine a default value.

In the case of initial access, TA is indicated via TAC of RAR(NTA=TA·16·64/2μ TA=0, 1, 2, . . . , 3846). Also, in other cases, TA isalso indicated via TAC of MAC CE.

(N _(TA_new) =N _(TA_old)+(T _(A)−31)·16·64/2^(μ) T _(A)=0,1,2, . . .,63).

-   -   (Operation Example 1-2): Reserved value of TA of MAC RAR is        used.

Specifically, the negative TA can be indicated by using reserved values(3847 to 4095) of TA (NTA=TA·16·64/2μ TA=0, 1, 2, . . . , 3846)specified in Release-15.

It should be noted that, considering that the number of reserved valuesis limited, a larger granularity than the TA of Release 15 may beapplied to the negative TA. For example, granularity may be applied asfollows.

N _(TA_negative)=(3846−T _(A_negative))*granularity,T_(A_negative)=3847,3848,3849, . . . ,4095  [Math. 1]

More specifically, in order to achieve the same range as the TAspecified in Release-15, the granularity may be about 15 times thegranularity of the TA of Release-15.

(3.2.3) Operation Example 2

In this operation example, the offset value indicating the relativeoffset with respect to the negative TA value is notified in thealignment of the UL transmission timing of the MT at the IAB node. Thatis, when the timing alignment of Case #7 is supported by the parentnode, the IAB node may configure the UL transmission timing (TA-Toffset)of the MT before the DL reception timing.

FIG. 10 illustrates an example of the timing alignment at the parentnode and the IAB node according to 3GPP Release-15 (Legacy), Case #6,and Case #7.

As illustrated in FIG. 10 , in the radio communication system 10, sincedifferent timing alignments can be performed, the TA value may benotified as follows.

-   -   (Alt. 1): TA_(CASE #7)=TA_(legacy)−Toffset    -   (Alt. 2): TA_(CASE #7)=TA_(case #6)−Toffset    -   (Alt. 3): Configuration is performed to indicate whether Toffset        is associated with Release-15 (legacy) or Case #6 It should be        noted that the default operation may be defined by TACASE        #7=TAlegacy−Toffset, as in Alt. 1.

Also, Toffset may be notified via MAC CE or RRC signaling. Toffset maybe indicated as follows.

-   -   (Alt. 1): Similar to Release-15 TA mechanism, the initial        Toffset is shown, and the gap between Toffset_new and        Toffset_old is shown so as to update Toffset.

For example, the initial Toffset is expressed as

N _(Toffset) *T _(c) ,N _(Toffset) =T _(Toffset)*granularity,T_(Toffset)=0,1,2, . . . ,k  [Math. 2]

It may be notified by MAC CE or RRC signaling. It should be noted thatthe granularity may be the same as TA of Release-15.

The update of Toffset is expressed as

Toffset=N _(Toffset) *T _(c) ,N _(Toffset_new) =N _(Toffset_old)+(T_(Toffset) −k)*granularity  [Math. 3]

It may be notified by MAC CE or RRC signaling. Here, k may indicate therange of each update, and the granularity may be the same as TA ofRelease-15.

-   -   (Alt. 2): The offset value is directly indicated.

Toffset=N _(Toffset) *T _(c) ,N _(Toffset) =T_(Toffset)*granularity  [Math. 4]

Also in this case, Toffset may be notified by MAC CE or RRC signaling.

(3.2.4) Operation Example 3

In this operation example, in order to realize Case #1 (the transmissiontimings of the DU of the parent node and the DU of the IAB node arematched), the timing matching mechanism specified in 3GPP Release-16 orT_delta is used.

Specifically, in the case of the DL transmission timing alignment of theDU of all related IAB nodes, the Release-16 mechanism may be followed,or the UL transmission timing aligning method of the MT in Case #6described above may be applied.

Alternatively, the DL transmission timing alignment of the DU of the IABnode may use the UL transmission timing of the MT in Case #7 asreference. As illustrated in FIG. 8 , the IAB node may configure the DLtransmission timing of the DU before the DL transmission timing((½)*TACase #7+(½)*T1) of the MT.

Also, in Release-16, the IAB node may configure the DL transmissiontiming (TA/2+T_delta) of the DU before the DL reception timing of the MTat the parent node, and T_delta may be configured as (−½) of the timinginterval between the DL transmission timing of the DU and the ULreception timing of the DU at the parent node.

In this operation example, the UL transmission timing of Case #7 is usedas a reference and the DL transmission timing of the DU is shown.Therefore, the following operation may be performed.

-   -   (Operation Example 3-1): Reuse T_delta of Release-16 and define        the operation of different IAB node as Release-16

That is, the IAB node configures the DL transmission timing ((½)*TACase#7−T_delta) of the DU before the DL reception timing of the MT. T_deltamay be configured as (−½) of the timing interval between the DLtransmission timing of the DU and the UL reception timing of the actualDU, based on the UL transmission timing of the MT of the parent node inCase #7.

-   -   (Operation Example 3-2): The operation of the IAB node in        accordance with Release-16 is reused and different instructions        of T1 are defined.

In this case, the IAB node may configure the DL transmission timing((½)*TACase #7−T1) of the DU before the DL reception timing of the MT.T1 may be configured as (−½) of the timing interval between the DLtransmission timing of the DU and the UL reception timing of the actualDU, based on the UL transmission timing of the MT of the parent node inCase #7. That is, in this case, T1 may be appropriately configured in ameaning different from the specified contents of T_delta of Release-16(gap between the DL transmission timing of the DU and the DL receptiontiming of the MT at the parent node). Furthermore, in this case, T1 maybe determined without depending on the implementation (capability) ofthe radio communication node such as the parent node.

(3.2.5) Operation Example 4

In this operation example, when Case #1/Case #6/Case #7 are dynamicallyswitched, which Case is applied is explicitly or implicitly indicatedfrom the parent node (or the CU 50) to the IAB node (or the child node).

As described above, in the radio communication system 10, Case #1/Case#6/Case #7 may be dynamically switched. In such a case, the operationassociated with the timing alignment described above may be dynamicallyswitched according to the applied Case.

-   -   (Operation Example 4-1): Whether the timing alignment according        to Case #1, Case #6, or Case #7 is applied is explicitly        indicated by downlink control information, for example, UL        scheduling grant DCI.    -   (Operation Example 4-2): Whether the timing alignment according        to Case #1, Case #6, or Case #7 is applied is determined by        whether simultaneous transmission is performed by using a        specific radio resource.

Specifically, when the simultaneous transmission of the DU and the MT isperformed, the UL transmission timing alignment according to Case #7 (orCase #6) is applied; otherwise, it may be determined (assumed) that theUL transmission timing alignment according to Case #1 is applied.

(4) Operation and Effect

According to the above-described embodiment, the following effects canbe obtained. Specifically, the radio communication node 100A (parentnode) can determine the alignment value (negative TA) of the ULreception timing based on the timing information (TA) used fordetermining the UL transmission timing, or the offset value from the TA,and can transmit the determined alignment value or offset value to theradio communication node 100B (lower node).

Therefore, even when Case #7 is supported, the IAB node can perform thetiming alignment based on the alignment value or the offset value andcan match the DL and UL reception timings at the IAB node in addition toCase #1. That is, according to the radio communication system 10, thetransmission timing and the reception timing of the DU and MT can bereliably matched in the IAB.

In the present embodiment, for example, the radio communication node100B (LAB node) can align the DL transmission timing of the upper nodeand the DL transmission timing of the radio communication node 100Bbased on the time (T_delta) associated with the switching from ULreception to DL transmission.

Therefore, even when Case #7 is supported, the operation according toCase #1, specifically, the transmission timings of the DU of the parentnode and the DU of the IAB node can be more reliably matched.

In the present embodiment, when the timing according to Case #7 isaligned, the radio communication node 100B (IAB node) can implicitlydetermine the aligning method of the DL transmission timing and the ULreception timing, based on the downlink control information (DCI) fromthe upper node or the DL transmission timing and UL reception timing.

Therefore, even when the Case #1/Case #6/Case #7 are dynamicallyswitched, the DL transmission timing and the UL reception timing can bemore reliably matched.

(5) Other Embodiments

Although the contents of the present invention have been described withreference to the embodiments, the present invention is not limited tothese descriptions, and it will be obvious to those skilled in the artthat various modifications and improvements can be made thereto.

For example, in the above-described embodiments, the names of the parentnode, the IAB node, and the child node are used, these names may changeas long as the configuration of the radio communication node in whichthe radio backhaul between the radio communication nodes such as gNB andthe radio access with the UE are integrated is adopted. For example, thenames may be simply called a first node, a second node, or the like, ormay be called an upper node, a lower node or a relay node, anintermediate node, or the like.

Also, the radio communication node may be simply called a communicationdevice or a communication node, or may be read as a radio base station.

In the above-described embodiments, the terms “downlink (DL)” and“uplink (UL)” are used, but may be called by other terms. For example,the terms may be replaced or associated with the terms such as forwardlink, reverse link, access link, and backhaul. Alternatively, the termssuch as a first link, a second link, a first direction, and a seconddirection may be simply used.

Furthermore, the block configuration diagrams (FIGS. 3 and 4 ) used todescribe the above-described embodiments illustrate blocks of functionalunits. Those functional blocks (structural components) can be realizedby a desired combination of at least one of hardware and software. Arealization method for each functional block is not particularlylimited. That is, each functional block may be realized by one devicecombined physically or logically. Alternatively, two or more devicesseparated physically or logically may be directly or indirectlyconnected (for example, wired, or wireless) to each other, and eachfunctional block may be realized by these plural devices. The functionalblocks may be realized by combining software with the one device or theplural devices mentioned above.

Functions include judging, determining, determining, calculating,computing, processing, deriving, investigating, searching, confirming,receiving, transmitting, outputting, accessing, resolving, selecting,choosing, establishing, comparing, assuming, expecting, considering,broadcasting, notifying, communicating, forwarding, configuring,reconfiguring, allocating (mapping), assigning, and the like. Forexample, a functional block (structural component) that causestransmitting may be called a transmitting unit or a transmitter. For anyof the above, as explained above, the realization method is notparticularly limited to any one method.

Furthermore, the CU 50 and the radio communication nodes 100A to 100Cdescribed above can function as a computer that performs the processingof the radio communication method of the present disclosure. FIG. 13 isa diagram illustrating an example of a hardware configuration of thedevice. As illustrated in FIG. 13 , the device can be configured as acomputer device including a processor 1001, a memory 1002, a storage1003, a communication device 1004, an input device 1005, an outputdevice 1006, a bus 1007, and the like.

Furthermore, in the following explanation, the term “device” can bereplaced with a circuit, device, unit, and the like. Hardwareconfiguration of the device can be constituted by including one orplurality of the devices illustrated in the figure, or can beconstituted by without including a part of the devices.

The functional blocks of the device (see FIGS. 3 and 4 ) can be realizedby any of hardware elements of the computer device or a combination ofthe hardware elements.

Moreover, the processor 1001 performs computing by loading apredetermined software (program) on hardware such as the processor 1001and the memory 1002, and realizes various functions of the device bycontrolling communication via the communication device 1004, andcontrolling reading and/or writing of data on the memory 1002 and thestorage 1003.

The processor 1001, for example, operates an operating system to controlthe entire computer. The processor 1001 can be configured with a centralprocessing unit (CPU) including an interface with a peripheral device, acontrol device, a computing device, a register, and the like.

Moreover, the processor 1001 reads a program (program code), a softwaremodule, data, and the like from the storage 1003 and/or thecommunication device 1004 into the memory 1002, and executes variousprocesses according to the data. As the program, a program that iscapable of executing on the computer at least a part of the operationexplained in the above embodiments is used. Alternatively, variousprocesses explained above can be executed by one processor 1001 or canbe executed simultaneously or sequentially by two or more processors1001. The processor 1001 can be implemented by using one or more chips.Alternatively, the program can be transmitted from a network via atelecommunication line.

The memory 1002 is a computer readable recording medium and isconfigured, for example, with at least one of Read Only Memory (ROM),Erasable Programmable ROM (EPROM), Electrically Erasable ProgrammableROM (EEPROM), Random Access Memory (RAM), and the like. The memory 1002can be called register, cache, main memory (main storage device), andthe like. The memory 1002 can store therein a program (program codes),software modules, and the like that can execute the method according tothe embodiment of the present disclosure.

The storage 1003 is a computer readable recording medium. Examples ofthe storage 1003 include an optical disk such as Compact Disc ROM(CD-ROM), a hard disk drive, a flexible disk, a magneto-optical disk(for example, a compact disk, a digital versatile disk, Blu-ray(Registered Trademark) disk), a smart card, a flash memory (for example,a card, a stick, a key drive), a floppy (Registered Trademark) disk, amagnetic strip, and the like. The storage 1003 can be called anauxiliary storage device. The recording medium can be, for example, adatabase including the memory 1002 and/or the storage 1003, a server, orother appropriate medium.

The communication device 1004 is hardware (transmission/receptiondevice) capable of performing communication between computers via awired and/or wireless network. The communication device 1004 is alsocalled, for example, a network device, a network controller, a networkcard, a communication module, and the like.

The communication device 1004 includes a high-frequency switch, aduplexer, a filter, a frequency synthesizer, and the like in order torealize, for example, at least one of Frequency Division Duplex (FDD)and Time Division Duplex (TDD).

The input device 1005 is an input device (for example, a keyboard, amouse, a microphone, a switch, a button, a sensor, and the like) thataccepts input from the outside. The output device 1006 is an outputdevice (for example, a display, a speaker, an LED lamp, and the like)that outputs data to the outside. Note that, the input device 1005 andthe output device 1006 may be integrated (for example, a touch screen).

In addition, the respective devices, such as the processor 1001 and thememory 1002, are connected to each other with the bus 1007 forcommunicating information thereamong. The bus 1007 may be configured byusing a single bus or may be configured by using different buses foreach device.

Further, the device is configured to include hardware such as amicroprocessor, a digital signal processor (Digital Signal Processor:DSP), Application Specific Integrated Circuit (ASIC), Programmable LogicDevice (PLD), and Field Programmable Gate Array (FPGA). Some or all ofthese functional blocks may be realized by the hardware. For example,the processor 1001 may be implemented by using at least one of thesehardware.

Notification of information is not limited to that explained in theabove aspect/embodiment, and may be performed by using a differentmethod. For example, the notification of information may be performed byphysical layer signaling (for example, Downlink Control Information(DCI), Uplink Control Information (UCI), upper layer signaling (forexample, RRC signaling, Medium Access Control (MAC) signaling, broadcastinformation (Master Information Block (MIB), System Information Block(SIB)), other signals, or a combination of these. The RRC signaling maybe called RRC message, for example, or can be RRC Connection Setupmessage, RRC Connection Reconfiguration message, or the like.

Each aspect/embodiment described in the present disclosure may beapplied to at least one of Long Term Evolution (LTE), LTE-Advanced(LTE-A), SUPER 3G, IMT-Advanced, 4th generation mobile communicationsystem (4G), 5th generation mobile communication system (5G), FutureRadio Access (FRA), New Radio (NR), W-CDMA (registered trademark), GSM(registered trademark), CDMA2000, Ultra Mobile Broadband (UMB), IEEE802.11 (Wi-Fi (registered trademark)), IEEE 802.16 (WiMAX (registeredtrademark)), IEEE 802.20, Ultra-WideBand (UWB), Bluetooth (registeredtrademark), systems using other appropriate systems, and next-generationsystems extended based on them. Further, a plurality of systems may becombined (for example, a combination of at least one of the LTE and theLTE-A with the 5G).

As long as there is no inconsistency, the order of processingprocedures, sequences, flowcharts, and the like of each of the aboveaspects/embodiments in the present disclosure may be exchanged. Forexample, the various steps and the sequence of the steps of the methodsexplained above are exemplary and are not limited to the specific ordermentioned above.

The specific operation that is performed by the base station in thepresent disclosure may be performed by its upper node in some cases. Ina network constituted by one or more network nodes having a basestation, the various operations performed for communication with theterminal may be performed by at least one of the base station and othernetwork nodes other than the base station (for example, MME, S-GW, andthe like may be considered, but not limited thereto). In the above, anexample in which there is one network node other than the base stationis explained; however, a combination of a plurality of other networknodes (for example, MME and S-GW) may be used.

Information and signals (information and the like) can be output from anupper layer (or lower layer) to a lower layer (or upper layer). It maybe input and output via a plurality of network nodes.

The input/output information can be stored in a specific location (forexample, a memory) or can be managed in a management table. Theinformation to be input/output can be overwritten, updated, or added.The information can be deleted after outputting. The inputtedinformation can be transmitted to another device.

The determination may be made by a value (0 or 1) represented by one bitor by Boolean value (Boolean: true or false), or by comparison ofnumerical values (for example, comparison with a predetermined value).

Each aspect/embodiment described in the present disclosure may be usedseparately or in combination, or may be switched in accordance with theexecution. In addition, notification of predetermined information (forexample, notification of “being X”) is not limited to being performedexplicitly, it may be performed implicitly (for example, withoutnotifying the predetermined information).

Instead of being referred to as software, firmware, middleware,microcode, hardware description language, or some other name, softwareshould be interpreted broadly to mean instruction, instruction set,code, code segment, program code, program, subprogram, software module,application, software application, software package, routine,subroutine, object, executable file, execution thread, procedure,function, and the like.

Further, software, instruction, information, and the like may betransmitted and received via a transmission medium. For example, when asoftware is transmitted from a website, a server, or some other remotesource by using at least one of a wired technology (coaxial cable, fiberoptic cable, twisted pair, Digital Subscriber Line (DSL), or the like)and a wireless technology (infrared light, microwave, or the like), thenat least one of these wired and wireless technologies is included withinthe definition of the transmission medium.

Information, signals, or the like mentioned above may be represented byusing any of a variety of different technologies. For example, data,instruction, command, information, signal, bit, symbol, chip, or thelike that may be mentioned throughout the above description may berepresented by voltage, current, electromagnetic wave, magnetic field ormagnetic particle, optical field or photons, or a desired combinationthereof.

It should be noted that the terms described in this disclosure and termsnecessary for understanding the present disclosure may be replaced byterms having the same or similar meanings. For example, at least one ofa channel and a symbol may be a signal (signaling). Also, a signal maybe a message. Further, a component carrier (Component Carrier: CC) maybe referred to as a carrier frequency, a cell, a frequency carrier, orthe like.

The terms “system” and “network” used in the present disclosure can beused interchangeably.

Furthermore, the information, the parameter, and the like explained inthe present disclosure can be represented by an absolute value, can beexpressed as a relative value from a predetermined value, or can berepresented by corresponding other information. For example, the radioresource can be indicated by an index.

The name used for the above parameter is not a restrictive name in anyrespect. In addition, formulas and the like using these parameters maybe different from those explicitly disclosed in the present disclosure.Because the various channels (for example, PUCCH, PDCCH, or the like)and information element can be identified by any suitable name, thevarious names assigned to these various channels and informationelements shall not be restricted in any way.

In the present disclosure, it is assumed that “base station (BaseStation: BS)”, “radio base station”, “fixed station”, “NodeB”, “eNodeB(eNB)”, “gNodeB (gNB)”, “access point”, “transmission point”, “receptionpoint”, “transmission/reception point”, “cell”, “sector”, “cell group”,“carrier”, “component carrier”, and the like can be usedinterchangeably. The base station may also be referred to with the termssuch as a macro cell, a small cell, a femtocell, or a pico cell.

The base station can accommodate one or more (for example, three) cells(also called sectors). In a configuration in which the base stationaccommodates a plurality of cells, the entire coverage area of the basestation can be divided into a plurality of smaller areas. In each such asmaller area, communication service can be provided by a base stationsubsystem (for example, a small base station for indoor use (RemoteRadio Head: RRH)).

The term “cell” or “sector” refers to a part or all of the coverage areaof a base station and/or a base station subsystem that performscommunication service in this coverage.

In the present disclosure, the terms “mobile station (Mobile Station:MS)”, “user terminal”, “user equipment (User Equipment: UE)”, “terminal”and the like can be used interchangeably.

The mobile station is called by the persons skilled in the art as asubscriber station, a mobile unit, a subscriber unit, a radio unit, aremote unit, a mobile device, a radio device, a radio communicationdevice, a remote device, a mobile subscriber station, an accessterminal, a mobile terminal, a radio terminal, a remote terminal, ahandset, a user agent, a mobile client, a client, or with some othersuitable term.

At least one of a base station and a mobile station may be called atransmitting device, a receiving device, a communication device, or thelike. Note that, at least one of a base station and a mobile station maybe a device mounted on a moving body, a moving body itself, or the like.The moving body may be a vehicle (for example, a car, an airplane, orthe like), a moving body that moves unmanned (for example, a drone, anautomatically driven vehicle, or the like), a robot (manned type orunmanned type). At least one of a base station and a mobile station canbe a device that does not necessarily move during the communicationoperation. For example, at least one of a base station and a mobilestation may be an Internet of Things (IoT) device such as a sensor.

Also, a base station in the present disclosure may be read as a mobilestation (user terminal, hereinafter the same). For example, each of theaspects/embodiments of the present disclosure may be applied to aconfiguration that allows a communication between a base station and amobile station to be replaced with a communication between a pluralityof mobile stations (for example, may be referred to as Device-to-Device(D2D), Vehicle-to-Everything (V2X), or the like). In this case, themobile station may have the function of the base station. Words such as“uplink” and “downlink” may also be replaced with wording correspondingto inter-terminal communication (for example, “side”). For example,terms an uplink channel, a downlink channel, or the like may be read asa side channel.

Likewise, a mobile station in the present disclosure may be read as abase station. In this case, the base station may have the function ofthe mobile station.

The radio frame may include one or more frames in the time domain. Eachof one or more frames in the time domain may be called a subframe.

The subframe may also include one or more slots in the time domain. Thesubframe may have a fixed time length (for example, 1 ms) that does notdepend on numerology.

The numerology may be a communication parameter applied to transmissionand/or reception of a certain signal or channel. The numerology mayindicate, for example, at least one of subcarrier spacing (SCS),bandwidth, symbol length, cyclic prefix length, transmission timeinterval (TTI), number of symbols per TTI, radio frame configuration,specific filtering processing performed by the transceiver in thefrequency domain, and specific windowing processing performed by thetransceiver in the time domain.

The slot may include one or more symbols (Orthogonal Frequency DivisionMultiplexing (OFDM) symbols, Single Carrier Frequency Division MultipleAccess (SC-FDMA) symbols or the like) in the time domain. The slot maybe the time unit based on the numerology.

The slot may include a plurality of minislots. Each minislot may includeone or more symbols in the time domain. The minislot may also be calleda subslot. The minislot may include fewer symbols than the slot. ThePDSCH (or PUSCH) transmitted in the time unit larger than the minislotmay be called PDSCH (or PUSCH) mapping type A. The PDSCH (or PUSCH)transmitted by using the minislot may be called PDSCH (or PUSCH) mappingtype B.

The radio frame, the subframe, the slot, the minislot, and the symbolall represent the time unit for signal transmission. The radio frame,the subframe, the slot, the minislot, and the symbol may have differentnames corresponding thereto.

For example, one subframe may be called the transmission time interval(TTI), the plurality of consecutive subframes may be called the TTI, andone slot or one minislot may be called the TTI. That is, at least one ofthe subframe and the TTI may be a subframe (1 ms) in the existing LTE,may be shorter than 1 ms (for example, 1-13 symbols), and may be longerthan 1 ms. It should be noted that the unit indicating the TTI may becalled the slot, the minislot, or the like, instead of the subframe.

Here, the TTI refers to, for example, the minimum time unit ofscheduling in the radio communication. For example, in the LTE system,the base station performs scheduling for allocating radio resources(frequency band width usable in each UE, transmission power, or thelike) to each UE in the units of TTI. The definition of the TTI is notlimited thereto.

The TTI may be a transmission time unit of a channel-encoded data packet(transport block), a code block, a codeword, or the like, or may be aprocessing unit such as scheduling or link adaptation. It should benoted that, when the TTI is given, the time interval (for example, thenumber of symbols) in which the transport block, code block, codeword,or the like are actually mapped may be shorter than that of the TTI.

It should be noted that, when one slot or one minislot is called theTTI, one or more TTIs (that is, one or more slots or one or moreminislots) may be the minimum time unit of scheduling. Also, the numberof slots (number of minislots) that constitutes the minimum time unit ofthe scheduling may be controlled.

The TTI having a time length of 1 ms may be called normal TTI (TTI inLTE Rel. 8-12), normal TTI, long TTI, normal subframe, normal subframe,long subframe, slot, or the like. The TTI that is shorter than thenormal TTI may be called shortened TTI, short TTI, partial TTI (orfractional TTI), shortened subframe, short subframe, minislot, subslot,slot, or the like.

It should be noted that long TTI (for example, normal TTI, subframe, orthe like) may be replaced with a TTI having a time length exceeding 1ms, and the short TTI (for example, shortened TTI) may be read as a TTIhaving a TTI length that is less than the long TTI length and greaterthan or equal to 1 ms.

The resource block (RB) is a resource allocation unit in the time domainand the frequency domain, and may include one or more consecutivesubcarriers in the frequency domain. The number of subcarriers includedin the RB may be the same regardless of the numerology and may be, forexample, 12. The number of subcarriers included in the RB may bedetermined based on the numerology.

Also, the time domain of the RB may include one or more symbols and mayhave a length of one slot, one minislot, one subframe, or one TTI. OneTTI, one subframe, or the like may include one or more resource blocks.

It should be noted that one or more RBs may be called a physicalresource block (Physical RB: PRB), a subcarrier group (Sub-CarrierGroup: SCG), a resource element group (Resource Element Group: REG), aPRB pair, an RB pair, or the like.

Also, the resource block may include one or more resource elements(Resource Element: RE). For example, one RE may be a radio resource areaof one subcarrier and one symbol.

The bandwidth part (BWP) (which may also be referred to as partialbandwidth) may indicate a subset of continuous common RBs (commonresource blocks) for a certain numerology in a certain carrier. Here,the common RB may be specified by the index of the RB based on thecommon reference point of the carrier. The PRB may be defined in the BWPand may be numbered in the BWP.

The BWP may include a BWP for UL (UL BWP) and a BWP for DL (DL BWP). Oneor more BWPs may be configured in one carrier for the UE.

At least one of the configured BWPs may be active, and the UE may notexpect to transmit or receive certain signals/channels outside theactive BWP. It should be noted that “cell”, “carrier”, or the like inthe present disclosure may be read as “BWP”.

The structures of the radio frame, the subframe, the slot, the minislot,the symbol, and the like described above are merely examples. Forexample, the configurations such as the number of subframes included inthe radio frame, the number of slots per subframe or radio frame, thenumber of minislots included in the slot, the number of symbols and RBsincluded in the slot or minislot, the number of subcarriers included inthe RB, and the number of symbols in the TTI, the symbol length, and thecyclic prefix (CP) length can be variously changed.

The terms “connected”, “coupled”, or any variations thereof, mean anydirect or indirect connection or coupling between two or more elements.Also, one or more intermediate elements may be present between twoelements that are “connected” or “coupled” to each other. The couplingor connection between the elements may be physical, logical, or acombination thereof. For example, “connection” may be read as “access”.In the present disclosure, two elements can be “connected” or “coupled”to each other by using one or more wires, cables, printed electricalconnections, and as some non-limiting and non-exhaustive examples, byusing electromagnetic energy having wavelengths in the radio frequencyregion, the microwave region and light (both visible and invisible)regions, and the like.

The reference signal may be abbreviated as Reference Signal (RS) and maybe called pilot (Pilot) according to applicable standards.

As used in the present disclosure, the phrase “based on” does not mean“based only on” unless explicitly stated otherwise. In other words, thephrase “based on” means both “based only on” and “based at least on”.

The “means” in the configuration of each device may be replaced with“unit”, “circuit”, “device”, and the like.

Any reference to an element using a designation such as “first”,“second”, and the like used in the present disclosure generally does notlimit the amount or order of those elements. Such designations can beused in the present disclosure as a convenient way to distinguishbetween two or more elements. Thus, the reference to the first andsecond elements does not imply that only two elements can be adopted, orthat the first element must precede the second element in some or theother manner.

In the present disclosure, the used terms “include”, “including”, andvariants thereof are intended to be inclusive in a manner similar to theterm “comprising”. Furthermore, the term “or” used in the presentdisclosure is intended not to be an exclusive disjunction.

Throughout this disclosure, for example, during translation, if articlessuch as “a”, “an”, and “the” in English are added, in this disclosure,these articles shall include plurality of nouns following thesearticles.

The term “determining” and “determining” as used in the presentdisclosure may encompass various operations. The “determining” and the“determining” may include, for example, “determining” or “determining”of judging, calculating, computing, processing, deriving, investigating,looking up, search, inquiry (for example, searching in a table, adatabase, or another data structure), ascertaining, and the like. Also,the “determining” and the “determining” may include “determining” and“determining” of receiving (for example, receiving information),transmitting (for example, transmitting information), input, output,accessing (for example, access to data in the memory), and the like.Also, the “determining” and the “determining” may include “determining”and “determining” of resolving, selecting, choosing, establishing,comparing, and the like. That is, the “determining” and the“determining” may include “determining” and “determining” of operations.Also, the “determining (determining)” may be read as “assuming”,“expecting”, “considering,” and the like.

In the present disclosure, the term “A and B are different” may mean “Aand B are different from each other”. It should be noted that the termmay mean “A and B are each different from C”. Terms such as “leave”,“coupled”, or the like may also be interpreted in the same manner as“different”.

Although the present disclosure has been described in detail above, itwill be obvious to those skilled in the art that the present disclosureis not limited to the embodiments described in this disclosure. Thepresent disclosure can be implemented as modifications and variationswithout departing from the spirit and scope of the present disclosure asdefined by the claims.

Therefore, the description of the present disclosure is for the purposeof illustration, and does not have any restrictive meaning to thepresent disclosure.

REFERENCE SIGNS LIST

-   10 Radio communication system-   50 CU-   100A, 100B, 100C Radio communication node-   110 Radio transmitting unit-   120 Radio receiving unit-   130 NW IF unit-   140 Control unit-   150 Timing related information transmitting unit-   161 Radio transmitting unit-   162 Radio receiving unit-   165 Downlink control information receiving unit-   170 Control unit-   200 UE-   1001 Processor-   1002 Memory-   1003 Storage-   1004 Communication device-   1005 Input device-   1006 Output device-   1007 Bus

1. A radio communication node comprising: a control unit configured to,when a transmission timing of a downlink and a reception timing of anuplink at a lower node are aligned, determine an alignment value of thereception timing based on timing information used to determinetransmission timing of the uplink, or an offset value from the timinginformation; and a transmitting unit configured to transmit thealignment value or the offset value to the lower node.
 2. The radiocommunication node according to claim 1, wherein the control unit isconfigured to align the transmission timing of the downlink at an uppernode and the transmission timing of the downlink at the radiocommunication node, based on time for switching from reception of theuplink to transmission of the downlink.
 3. A radio communication nodecomprising: a control unit configured to, when a transmission timing ofa downlink and a reception timing of an uplink at the radiocommunication node are aligned, determine an aligning method of thetransmission timing of the downlink and the reception timing of theuplink, based on downlink control information from an upper node, or thetransmission timing of the downlink and the reception timing of theuplink; and a transceiving unit configured to receive the uplink from alower node and transmit the downlink to the lower node, based on thedetermined aligning method.